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 * or LICENSE.txt.  See the License for the specific
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package org.glassfish.grizzly.http2;

import org.glassfish.grizzly.Buffer;
import org.glassfish.grizzly.http2.hpack.Encoder;
import org.glassfish.grizzly.memory.CompositeBuffer;
import org.glassfish.grizzly.memory.MemoryManager;

import java.util.Map;

/**
 *
 * @author oleksiys
 */
public class HeadersEncoder {

    private static final String DEFAULT_BUFFER_SIZE_PROP_NAME =
            "org.glassfish.grizzly.http2.HeadersEncoder.DEFAULT_BUFFER_SIZE";
    private static final String DEFAULT_BUFFER_SIZE_STRING = "8192";

    private static final int DEFAULT_BUFFER_SIZE =
            Integer.parseInt(System.getProperty(DEFAULT_BUFFER_SIZE_PROP_NAME, DEFAULT_BUFFER_SIZE_STRING));

    private final Encoder hpackEncoder;
    private final MemoryManager memoryManager;

    private CompositeBuffer buffer;

    public HeadersEncoder(final MemoryManager memoryManager,
                          final int maxHeaderTableSize) {
        this.memoryManager = memoryManager;
        hpackEncoder = new Encoder(maxHeaderTableSize);
    }
    
    public void encodeHeader(final String name, final String value, final Map<String,String> capture) {
        if (capture != null) {
            capture.put(name, value);
        }
        init();
        hpackEncoder.header(name, value);
        while (!hpackEncoder.encode(buffer)) {
            buffer.append(memoryManager.allocate(DEFAULT_BUFFER_SIZE));
        }
    }
    
    public Buffer flushHeaders() {
        final Buffer bufferLocal = buffer;
        bufferLocal.trim();
        buffer = null;

        return bufferLocal;
    }

    private void init() {
        if (buffer == null) {
            buffer = CompositeBuffer.newBuffer(memoryManager);
            buffer.allowInternalBuffersDispose(true);
            buffer.allowBufferDispose(true);
            buffer.append(memoryManager.allocate(DEFAULT_BUFFER_SIZE));
        }
    }
}
